Insecticide



Faiented Sept. 3, 1940 ,z gzr Riihm & Haas Company,

Philadelphia, Pa.

No Drawing. Applieation Api-il' 19, rest,

Serial N 02 268,695

This inventiton relates sitions and particularly to the use of certainsubstituted phenyl benzyl ethers and thio ethers as the active principlethereof. It is a continuation-in-part of copending application, SerialNo. 141,927, filed May 11, 1937, now U. S. Patent No. 2,159025, grantedMay 23, 1939.

The object of the invention is to provide improved insecticidalcompositions of general application which can be used in'low'concentration to control pests without injury to plant foliage. Afurther object is to provide an organic insecticide of place of leadarsenate, etc., against sects such as bean beetles, etc.

A still further object relating to and growing out of the accomplishingof the foregoing objects chewing inis to provide an efficient method forthe preparation of phenyl benzyl ethers in high yields.

The phenyl ethers and benzyl ethers have heretofore been proposed asinsecticidal principles. However, they have never been used extensivelyfor the purpose because of their relatively low toxicity as compared toother known insecticidal principles and because of the severe plantinjury that results from their use in sufiicient quantities to beeffective against insects. It has now been found, however, thattheintroduction of certain substituents into either the phenyl or benzylgroup has the eifect of greatly reducing the corrosiveness of phenyl,benzyl ethers to plant foliage, while in many instances increasing thetoxicity of the base compound. By a series of many hundred tests onphenyl benzyl ethers'having various substituents in the phenyl and/orbenzyl nucleus, it has been established that substituents having anatomic or relative group weight of at least 30 and which are notthemselves corrosive, such as strongly acid or basic groups and thephenolic hydroxyl group, either greatly reduce plant foliageinjury ascompared with equal proportions of the unsubstituted compound or sogreatly increase the toxicity that by using smaller dosages, plantinjury can be avoided while maintaining effective insect control.Substituents of a total relative weight less than 30 are apparently toosmall to be effective.

Among the substituent groups that have been found to produce this effectmay be mentioned the alkyl groups of more than 2 carbon atoms, thealkylene groupsof similar carbon content, hydroaromatic groups, aralkylgroups, alkoxy groups, aryloXy groups, acyl groups, halogen atoms, nitrogroups, amino groups that have been neutralized, acylamino, alkylaminoand aralkylamino groups, and carboxyl and sulfonic groups that have beenneutralized as by being converted to a salt, ester, or lactone group. Ithas also been found that when the single aroto insecticidal compo-v theso-called stomach type to-be used in considered as substituted phenylgroups. The

substituent group may be in either the ortho, meta, or para position tothe CHzQ-- linkage but preferably is in the para where its influence instomach poisons is generally the greatest. In compounds to be usedsolely as contact insecticides, the substituent in the ortho position-ispreferred. A plurality of substituents. either similar or dissimilar andeither situated on the one or on both aromatic rings, is included.Compounds with substituents in the methylene group are also included.

These compounds may be made in any of the known methods all of which inprinciple involve condensing in an alkaline medium the properlysubstituted phenyl with benzyl chloride containing the desiredsubstituents, if any, in the benzyl group. An improved method that hasbeen found particularly satitsfactory and which is a feature of thisinvention is the utilization of dimethylaniline in amounts substantiallyless than equimolecular with the benzyl chloride in conjunction with analkali metal hydroxide as the condensing agent. In general this improvedmethod comprises mixing the phenol or the sodium salt of the phenolbeing condensed, a slight molar excess of the benzyl chloride,dimethylaniline in amounts approximately onehalf the molar quantity ofthe phenol or benzyl chloride, and an amount of alkali metal hydroxideequivalent to the amount of benzyl chloride in aqueous emulsion, heatinguntil reaction is substantially complete, filtering, and washing, andrecrystallizing or otherwisepurifying the product. The proportions heregiven are not critical but rather are those that have been found to givein general the most economical yields. Larger or smaller amounts ofdimethylaniline may he used. The following-examples are given toillustrate this method of preparation, wide variations in them beingpermissible.

EXAMPLE l..Pr"epamtion of C'GH5C'H2OC6H4- IVOz-4.A mixture of 3360 g.('14 mols) of 81.8% paranitro-sodium phenolate dihydrate, 2050 ,g. (15.4mols) of benzyl chloride, 848 g. (7 mols) oi dimethylaniline, 56 g. (1.4mol) of sodium hydroxide in 10 l. of water, was heated on a boilingwater bath for 6 hours, with stirring. It was allowed to standovernight, and. then was filtered. The filtrate was neutral to litmus.

The cake was ground and washed with 609 cc. (7 mols) of concentratedhydrochloric acid in 3 l. of water, and then with 400 cc. (4.? mols) ofacid in 10 l. of water. The solid was washed literature. When thedimethylaniline was replaced with sodium hydroxide the yield dropped to46%.

EXAMPLE 2.-Preparation of CsHsCHzOCsHr CoHs-2.--A mixture of 204:0- g.(12 mols) of o-phenylphenol, 1670 g. (13.2 mols) of benzyl chloride, 530g. (13.2 molsiof sodium hydroxide, 727 g. (6 mols) of dimethylaniline,in10 l of water, was heated to 100 C. and stirred at this temperaturefor 4 hours. The mixture was allowed to cool overnight and the topaqueous layer was siphoned off. A mixture of 3.5 l. of ethylenedichloride and 3.5 l. of water containing 50 g. of sodium hydroxide wasadded to the bottom layer, and after stirring, allowed to separate. Thebottom layer was washed with '7 l. of water and then three times with520 cc. (6 mols) of concentrated hydrochloric acid in 3.5 l. of water.The bottom layer was washed three times with '1 l. of water. Theethylene dichloride solution was dried over calcium chloride,concentrated, dissolved in 6.3 i. of methanol, and cooled to 0. Thecrystalline product was filtered off and air-dried. The total weight was2880 g., or 92.3% of the theoretical yield. Melting point 423 C. When363 g. (3 mols) or 0.25 molecular equivalents of dimethylaniline wasused, the yield was only 79%.

ExAMrLa 3.-Preparation of CeHsCH2OCcH4- C(CHa)a-4.A mixture of 150 g. (1mol) of ptertiary-butylphenol, 62 g. (0.5 mol) of dimethylaniline, 139g. (1.1 mol) of benzyl chloride, 44 g. (1.1 mol) of sodium hydroxide in540 cc. of water, was stirred and heated on a boiling water bath for 4hours. The mixture was rapidly cooled and to it was added 50 cc. (0.5mol) of concen trated hydrochloric acid. The solid was washed twice bymelting in the presence of 0.5 mol of hydrochloric acid in 700 cc. ofwater, and then washed twice with water. It was recrystallized from 350cc. of methanol, giving 200 g. or 83% yield. Melting point 64 C.

EXAMPLE L-Preparattcm of 4-NO2CeH4C'Hs-. OCsHsCwHah-F-Qrudep-nltrobenzyl bromide was prepared by the method of 0rg.'Syn. XVL, 54.

A mixture of 400 g. of this crude material (1.33 mol), 200 g. (1.33 mol)of p-tertlary butylphenol, 60 g. (1.5 mol) of sodium hydroxide in 1 l.of water, was heated on a boiling water bath and stirred for 2 hours.After cooling overnight, the resulting solid was transferred to aBiichner funnel and washed with 100 cc. of 50% methanol and with 100 cc.of 75% methanol. A small amount of olaclr oil filtered through. Theproduct was then recrystallized from 800 cc. of methanol twice, as lighttan crystals melting at 80. The yield of Y-nitrobenzyl -tertiary-butylphenyl ether was 311 g., or 82%.

The phenyl benzyl ethers, having a substituent comprising a neutralizedacidic group, may he represented by the following general formulawherein Bz represents a benzyl group, Ph represents a phenyl nucleus, Yrepresents a member of the group consisting of hydrogen, aliphatichydrocarbon groups, and nltro groups, and A represents a neutralsubstituent selected from the group consisting of salts, esters, andamides of the -COOH and SO3H groups.

The best method of using these phenyl benzyl ethers in insecticidalcompositions will depend to a large extent on the particular insect orclass of insects which is being combated. When used to control chewinginsects such as the bean beetle they maybe applied as either-a dust or aspray in which the active ingredient varies from 0.05 to 5% of thetotal. The dusts are readily prepared by dissolving the ether in asuitable solvent such as'acetone, mixing the proper amount of solutionwith an inert powdered substance such as talc, lime, etc., and dryingwhile stirring the powder. Suitable formulae are the following- Parts byweight (a) Active ingredient 1 Talc or lime 98 Spreader (cetyl dimethyl,ethyl ammonium, ethyl sulfate) (b) Active ingredient 1 Alum sludge 48Lime 48 Soy bean oil 3 Sprays to combat chewing insects can be made byapplying a larger quantity of the active ingredient to a powder addingan emulsifying agent and dispersing in sufficient water to reduce thequantity of active ingredient in the final spray to the desiredconcentration. A suitable formula for this type of spray is- Parts 1part active ingredient deposited on 2 parts magnesium carbonate 3 Acommercial emulsifying agent sold under the name DX spreader Water 96.5

' water to reduce the concentration of active ingredient to the desiredpoint. A suitable formula for this type of spray 15-- Parts .25 partactive ingredient and .25 part emulsifying agent dissolved in .50 partpine oil 1 Water 100300 Spray used to combat flying insects such ascommon flies, mosquitoes. etc., can be made by merely dissolving theproper amount of active ingredient, 1-5%, in an organic solvent such askerosene to which a spreading agent may be added if desired.

The tables given below show the results of a number of tests usingvariously substituted phenyl benzyl ethers in combating the more commoninsects. There is also included for purposes of comparison the resultsobtained when the unsubstituted compound is used.

Table I gives the results of toxicity tests of 1% dusts or spraysagainst bean beetle larvae. These tests were made under controlledtemperature, humidity and light conditions. The bean plants were sprayedor dusted 24 hours before the Mexican bean beetle larvae wereintroduced. Counts were made at the end of 96 hours. At least threeexperiments were run on each compound and the figures given are theaverage. Checks were made in each case with magnesium arsenate.

Table II gives the results of a similar series of tests performed onbean beetle adults. These tests were made under the same conditionsgiven for Table I excepting that the bean beetle adults were usedinstead of the larvae.

2,213,218 '3 Table I Mg. arsenate Formlfla Plant Kill, Incap.,

I percent percent Km, heap" percent percent CoHsCHgOC'eH; 13 6 40 3CcHsCHgO C H4C (CHt)a-4 N 76 10 40 3 CQHQCHIOCHJO (0110302154-. 80 13 403 04H H 73 13 40 3 C 46 23 43 23 60 16 43 23 .83 10 40 3 53 10 35 13 6030 v 30 6 73 23 30 6 H1O CaHu(2-NO:)S 16 23 30 64'NO1CQH4OH2OGIH40(CH3)3-'1- 93 3 35 13 4-NO2C1H4CH2O CeH4CH:-4 66 l 3513 1-C oH1CH2OCuH5 30 23 30 6 I (CcHghCHOCeHs 10 20 35 13 In theforegoing tables the tests summarized used the substituted phenyl benzylethers as stomach poisons. The tables that follow show the results oftests in which they are used as contact -poisons. Table IV shows theirtoxicity Table II Mg arsenate Formula Plant K111, 111081, M inj. percentpercent Km heap" percent percent CQHQCHQOCBHL- Severe 15 20CuH5CH2OCoH4CH: Fat 13 3 23 a aCHzOCnHfiHa l 25 CaHsCHz0CuH4C(C a)r 20 6l CqHsCHzOCaH4C CH3 2CH2C 43 3 l5 CuH CHzOCeH4C(CHa)2CH2C(CH 13 0 20CuH5CHzOCeH4COCHa-4 10 16 CqH5CHzOC-aH4CaH5-2 20 10 16 CuHtOHzOCiHiCl-i43 6 16 CtHsCHzOCaHqNOH.-. 3O 10 16 CaHsOHzOCoELN 022. Q. 23 3 16CeH5CH2OC1oH7-1 16 10 16 CaH5CH OC 0H7-2; 16 3 16 1, 3-(CoH.sCHzO)iGtH4l3 0 l6 (CaH5CH20 a 4-):4C(CHQ2 0 l0 CliHsCHzQCaHaNOrZ-Cl-. 23 13 16CaH5CHzsCuH4NO2-4 26 6 16 CaH CHzSCuH3(N02)r2, 4. 10 0 10 OeHsCHnOCUH4NHCOCH3 16 16 GaHaCHaOCsHlCOOZn/a- 20 5 10 CuH CHzOCuH4SO3NH3CaH4CH13 O 16 4-NO2CoH4CHz0CaH5 36 6 l0 4NOzCuH4CHzOCH4N0z-2 16 3 134-NOzCaH4CH2OCoH4C1-A. 3O 13 13 4-NO2C6H4CH2OCBH4CBH5-2. 16 0 262-C1COH4GH2OCGH4C (CH:)2CH:C (0 39M l3 0 33 3 2-C1CaH4CHzOCaH4NO2-4 5515 30 5 2'O1C6HQOHQOCIIHICI4 50 5 5 2-C1CeH4CH2OCoH4CoHa-2 3O 6 3 3NO-4-CH3OCBHGCHZOO6HL 30 13 30 3 1-CwH1CHg0CaH4C1-4 35 10 25 51-C1oH7CHn0CnH4CaH5-2. 30 10 30 3 2-C oH C1120C5H4C(CH3)3-4 30 0 36 3Z-CmHuCHzOCaH C(CHa)zCH C (CH3)3-4 26 3 36 3 fl-owHncflzocoHicsHrz 20 535 5 Table m shows the effectiveness of the new insecticides againscabbage worm larvae. The procedure was the same as for Tables I and IIexcept the test organism was the larva of the dia against red spiders.In' all these tests the insecticide was applied as an emulsion spray inwhich the toxic material being tested was diluted 1:1200 times unlessotherwise indicated. At this mond-back cabbage worm. dilution no foliageinjury was observed with any Table III Mg arsenete Formula 13 1: PercentM gffim Incap.

I Lead arsenate used in check in place 0! magnesiuni arsenate.

of the materials tested. The tests were made by spraying the emulsionunder standard conditions on foliage infested with red spiders(Araneida). The host plants were ageratum, bean, and cabbage. The plantswere allowed to stand for 24 hours and then counts were made on fivepieces of the plant for each test. The figures given are the averagepercent kill.

Table IV Per Formula cent kill CsHsCHzOCgHs 26 5 CsH5CHzOCaH|CH3-3. 41CQHBCHZOCQH3(CH 96 CsH5CH7OCsH3-3-CH3-6- 83 CQHLCHQOCGHCH(CH3)C1H54-;..82 CsH5CHaOCH4C(CH:)3-4 83 Co s H aH4C(CH1)2CzHs-4 57 CflH5CH"oCflH10CI'i-2. 57 CoH5CHQOCnH4CH1CH=C 6O 2O CellsCIlnOColIrCOCHs-Z 81C5H5CHzOCsniCnH5-2" Q1 CgH5CHzOCsH4Cl-2 R3 CgIhCHzOCuHrNOz-Z (dilution1:800) ad CgHsCHzOCaIlflN0z)2'2,6-C(CH3)2CH1C(CH3)3-4 64 0511501120010182 1.3-(C5H5CH20MC0H4 51 CH CHzOCsHsNO2-2-Cl-4.. 81 CHsCHzSCaH4 Oz 53CQHBCHQOCQIICOZCHB 88 CflH5CH2OC6H4CO2Cg2CIH2SCN 2 52 osmcmo =0 Table Vsummarizes similar tests against mealy bugs. The tests were conducted inthe same manner as in Table IV excepting that the organisms were mealybugs and the host plant coleus' Table V 46 Per- Formula cent killC5H5CH1OC5H5 12 OCaH|CHs-3. 17 18 53 71 55 51 57 91 58 54 CAI CIIOCBiI4CUH5-Z 5B HH CHzOCnH NOz-4 48 C5H5CH2OCnH4COzCH2CHzSCN-24-NOQCEIILCIiZOClIIQCIIJ-3 A.

Table VI summarizes tests performed as in Tables IV and V on aphisinfesting nasturtium and cabbage plants.

Table VI Per cent kill Formula Finally, Table VII gives data on flytests conducted by the standardized procedure oi! the approvedPeet-Grady method. In these tests a 2% solution of the indicated phenylbenzyl ether in kerosene was used.

Additional compounds that have been tested and which show a much reducedcorrosiveness to plants as compared to the unsubstituted phenyl benzylethers without sacrifice of toxicity are:

From the data herein contained it is apparent that those phenyl benzylethers having a substantially neutral substituent of atomic or relativegroup weight of at least 30 or less corrosive to plants than theunsubstituted or less highly substituted ones. Also that they have awide range of usefulness in combating insect pests. Additionalsubstituent groups and other ways of using those herein disclosed willbe apparent to persons skilled in the art. It is intended that suchmodifications as do not depart from the basic concept of the inventionare to be included in the appended claims.

I claim:

1. An agricultural insecticidal composition suitable for use on livingplants which contains a phenyl benzyl other of the general formulawherein 132 represents a benzyl group, Ph represents a phenyl mucleus, Yrepresents a member of the group consisting of hydrogen, aliphatichydrocarbon groups, and nitro groups, and A represents a neutralsubstituent selected from the group consisting of salts, esters, andamides of the COOH and SO3H groups.

2. An agricultural insecticidal composition suitable for useon livingplants which contains a phenyl benzyl ether of the formula BRO-P11wherein 132 represents a benzyl group, Ph represents a phenyl nucleus, Yrepresents hydrogen,

and A represents a neutralized carboxyl group.

3. An agricultural suitable for use on living plants containing ainsecticidal composition phenyl benzyl ether that is phenyl substitutedby a methyl ester of a carboxyl group.

4. An insecticidal composition containing the benz yl ether of 2-hydroxymethyl benzoate. 5. An agricultural insecticidal composition suitablefor use on living plants which contains a phenyl benzyl ether 01' theformula F. HES'I'ER.

hydrogen, I

